Title:New insights on the formation of supersaturated solid solutions in the Cu Cr system deformed by high pressure torsion

Abstract: In the Cu Cr system, the formation of supersaturated solid solutions can be
obtained by severe plastic deformation. Energy dispersive synchrotron
diffraction measurements on as deformed Cu Cr samples as a function of the
applied strain during deformation confirm the formation of supersaturated solid
solutions in this usually immiscible system. Due to evaluation of the
diffraction data by a newly developed energy dispersive Rietveld program,
lattice parameter and microstructural parameters such as domain size and
microstrain are determined for as deformed as well as annealed samples. The
obtained information is used to deepen the understanding of the microstructural
evolution and the formation of supersaturated solid solutions during severe
plastic deformation. Complimentary transmission electron microscopy
investigations are furthermore performed to characterize the evolving
microstructure in detail. After annealing at elevated temperatures, the formed
solid solutions decompose. Compared to the as deformed state, an enhanced
hardness combined with a high thermal stability is observed. Possible
mechanisms for the enhanced hardness are discussed.